The only way that I could cut off the knots on my Persian/Himalyian was to snip one snip at a time with a very sharp pair of cuticle sissors. One snip and he would be gone - and he was quite a friendly guy - don't know how you could do it with a wild sort of cat. But after days of getting after him and snipping every chance that I could - with the help of others in the house petting him, etc. we would get off some of the very biggest knots.